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diff --git a/Documentation/userspace-api/media/dvb/fe-type-t.rst b/Documentation/userspace-api/media/dvb/fe-type-t.rst new file mode 100644 index 000000000..e89862548 --- /dev/null +++ b/Documentation/userspace-api/media/dvb/fe-type-t.rst @@ -0,0 +1,91 @@ +.. SPDX-License-Identifier: GFDL-1.1-no-invariants-or-later + +************* +Frontend type +************* + +For historical reasons, frontend types are named by the type of +modulation used in transmission. The fontend types are given by +fe_type_t type, defined as: + + +.. c:type:: fe_type + +.. tabularcolumns:: |p{6.6cm}|p{2.2cm}|p{8.5cm}| + +.. flat-table:: Frontend types + :header-rows: 1 + :stub-columns: 0 + :widths: 3 1 4 + + + - .. row 1 + + - fe_type + + - Description + + - :ref:`DTV_DELIVERY_SYSTEM <DTV-DELIVERY-SYSTEM>` equivalent + type + + - .. row 2 + + - .. _FE-QPSK: + + ``FE_QPSK`` + + - For DVB-S standard + + - ``SYS_DVBS`` + + - .. row 3 + + - .. _FE-QAM: + + ``FE_QAM`` + + - For DVB-C annex A standard + + - ``SYS_DVBC_ANNEX_A`` + + - .. row 4 + + - .. _FE-OFDM: + + ``FE_OFDM`` + + - For DVB-T standard + + - ``SYS_DVBT`` + + - .. row 5 + + - .. _FE-ATSC: + + ``FE_ATSC`` + + - For ATSC standard (terrestrial) or for DVB-C Annex B (cable) used + in US. + + - ``SYS_ATSC`` (terrestrial) or ``SYS_DVBC_ANNEX_B`` (cable) + + +Newer formats like DVB-S2, ISDB-T, ISDB-S and DVB-T2 are not described +at the above, as they're supported via the new +:ref:`FE_GET_PROPERTY/FE_GET_SET_PROPERTY <FE_GET_PROPERTY>` +ioctl's, using the :ref:`DTV_DELIVERY_SYSTEM <DTV-DELIVERY-SYSTEM>` +parameter. + +In the old days, struct :c:type:`dvb_frontend_info` +used to contain ``fe_type_t`` field to indicate the delivery systems, +filled with either ``FE_QPSK, FE_QAM, FE_OFDM`` or ``FE_ATSC``. While this +is still filled to keep backward compatibility, the usage of this field +is deprecated, as it can report just one delivery system, but some +devices support multiple delivery systems. Please use +:ref:`DTV_ENUM_DELSYS <DTV-ENUM-DELSYS>` instead. + +On devices that support multiple delivery systems, struct +:c:type:`dvb_frontend_info`::``fe_type_t`` is +filled with the currently standard, as selected by the last call to +:ref:`FE_SET_PROPERTY <FE_GET_PROPERTY>` using the +:ref:`DTV_DELIVERY_SYSTEM <DTV-DELIVERY-SYSTEM>` property. |